1. Field of the Invention
The present invention relates to high power low frequency transducers, and, more particularly, to high power low frequency transducers having a magnetic structure with an air gap and a voice coil located in the air gap.
2. Description of the Related Art
A high power low frequency transducer, commonly referred to as a “loudspeaker,” has a magnetic structure with “air gaps” and voice coils that are located in the air gap(s). At normal operating sound pressure levels, it is common for the voice coil temperature to reach 280° C. (536° F.). This high temperature has the deleterious effect of reducing the transducer's efficiency and reliability. Known techniques for reducing the voice coil temperature include using air circulation to cool the voice coil, but these known techniques have not provided sufficient air flow in terms of volume and velocity in order to be effective.
Another problem with known high power loudspeakers is that the extreme force involved in oscillating the voice coil in axial directions sometimes results in physical damage to the loudspeaker. For example, the inertia of the moving voice coil may cause the voice coil to oscillate beyond a safe range of movement, thereby resulting in collisions between speaker components, or pulling speaker components apart from one another.
What is neither disclosed nor suggested by the prior art is a high power low frequency transducer in which the operating temperature of the voice coil is effectively limited to thereby preserve the voice coil's efficiency and reliability, and in which the range of movement of the voice coil is effectively limited to thereby prevent damage to the transducer.